Fix the setup/teardown urchin test scripts under zsh

The v* glob expansions were failing with an error under zsh, just set
nullglob/NULL_GLOB and make both bash and zsh happier.

test/fast/setup_dir

@@ -4,6 +4,9 @@
   cd ../..
 
   # Back up
+
+  type setopt >/dev/null 2>&1 && setopt NULL_GLOB
+  type shopt >/dev/null 2>&1 && shopt -s nullglob
   mkdir -p bak
   mv v* src alias bak || sleep 0s
 )